The research focuses mainly on the development of form perception during early infancy. It is argued that a general approach to the development of infant form perception, based on the contrast sensitivity function, may require integration with recently reported characteristics of infant threshold and suprathreshold form perception to extend these models to everyday situations. The proposal consists of three related lines of research. The first involves establishing a selective adaptation paradigm in infants to investigate the development of size-specific feature detectors, which are mechanisms that contribute to a number of processes in form perception. The second involves the development and function of contrast constancy. Infant preferential looking suggests important differences in threshold and suprathreshold form perception. Several experiments are proposed to investigate these differences. The effects of contrast levels on infants' preferences among two-dimensional forms will be assessed against the quantitative predictions of models of infant pattern preference. The role of contrast constancy in the development of infant face perception will be investigated. The effect of experience on mechanisms underlying contrast constancy will be examined in myopic children. The third line of research involves the development of form discrimination. Infants' ability to discern differences in pattern contrast will be assessed under threshold and suprathreshold conditions. The results will reflect the development of the dynamic properties of mechanisms that code for pattern contrast.